Adjustable die.



G. H. LEWIS.

ADJUSTABLE DIE.

APPLICATlON FILED JULY 14.191?- LQ5Q,821 Patented Jan. 8,1918

Z6 INVENTOR.

BY (QM Mim 7 M I :4TTORNEYS.

WI TNESSI warren snares rarnnr onrron.

GEORGE H. LEWIS, OF CHICOPEE FALLS, MASSACHUSETTS, ASSIGNOR TO THE FISK RUBBER COMPANY, OF CHICOPEE FALLS, MASSACHUSETTS, A. CORPORATION 0F MASSACHUSETTS.

nna'usratenn DIE.

Specification of Letters Patent.

Patented Jan. 8, 11913.

Application filed July 14, 1917. Serial No. 180,604.

To all whom it may concern:

Be it known that I, GEORGE H. LEWIS, a citizen of the United States of America, residing at Chicopee Falls, in the county of Hampden and State of Massachusetts, have invented certain new and useful Improvements in Adjustable Dies, of which the fol= v lowing is a specification.

This invention relates to improvements in adjustable dies, and while the invention is capable of general application, it finds one advantageous use in the die heads of tubing machines, such, for example, as are used in the rubber industry'for forming continuous tubes and strips of rubber of various cross sectional shapes and sizes.

In dealing with plastic and elastic material, such as rubber, for exam le, in die forming operations, special pro lems arise due to the peculiar physical properties of the material. More particularly, by reason of-the elasticity of the material, the article formed by the die may be larger than the die opening itself, due to the outward spring or swellage of the material after leaving the confines of the die. Succeeding batches of material are seldom uniform in elastic qualities, and it will, therefore, be apparent that unless some means are provided to compensate for varying degrees of elasticity, a product, non-uniform in size, may be obtained. This invention is concerned, among other things with the provision of a die head, wherein compensatory adjustments may be made from time to time as necessi tated by varying conditions in the material being handled or in the character of the,

work.

One object of the invention is to provide an improved die head, particularly adapted for use with plastic and elastic materials, wherein means are provided to adjust the die to compensate for variations in the elasticity of the material being handled, so that the product formed may be maintained substantially uniform as to size, despite the use of material of varying characteristics.

Another object of the invention is to provide a die headwherein the size and shape of the die opening may be varied in an improved manner, the construction being characterized by a flexible and adjustable arrangement whereby the die is adapted for a Wide range of work of varying character.

Another object of the invention is to provide in a die, means whereby the convergent choke passage leading to the die opening may be conveniently varied in respect to its degree of convergence, to control the flow of material to the die opening.

Other objects and advantages will appear in the following description and will be pointed out-in the appended claims.

The invention, in an embodiment at present preferred, is shown for illustrative purposes in the accompanying drawings, in-

filler plates used in the die head; and

Fig. 5 is a perspective view of a pattern for use in conveniently assembling the former strips in the die head to obtain a 'die opening of the desired size and shape.

The invention will be described herein in merely one of its specific uses; namely, as adapted for use in the die head of a tubing machine. The invention is, however, capable of other uses and the adaptation to be described is given merely for the purposes of illustration.

The tubing machine has not been illustrated in the'drawings, since it is unnecessary to an understanding of the invention.

The description of the die head as adapted for attachment to the outlet end of a tubing machine will sufiiciently disclose the in-- vention since tubing machines are now'well known in the art.

Referring to the. drawings; A represents a tubular male threaded portion adapted for connection to the outlet end of a tubing machine or any other suitable machine, the only essential of such a machine being a means for forcing material, such as rubber stock for example, into and through the tu bular member A. The latter is provided with a square head or flange (3 to the upper and lower edges of which top and bottom plates 7 and 8, respectively, are suitably secured, as indicatedin Fig. Side plates 9, formed integrally with a front plate 10, are secured to the side edges of flange 6 and cooperate with plates 7 and 8 to form ends resting upon the pattern.

a hollow boxlike incl'osure forwardly of the tubular member A. The front plate 10, however, is only substantially half as high as the inclosure itself so that a relatively large opening is formed in the front wall of the die head. Of course, it is obvious that this front plate as well as other parts may be made of different shapes so that the die opening will be made up under the invention according to the requirements of the product desired.

Secured to the side plates 9 and extending therebetween in spaced parallel relation across the space above plate 10 are cross bars 11. Behind the latter are a plurality of very thin flat strips 12, which are arranged to close the opening between the top plate 7 and the upper edge 13 of front plate 10, except for a small outlet opening 14. The strips 12 are each substantially ,equal in width to the thickness of front obvious manner. The strips '12 may be also forced together laterally by thrust plates 18, one on each side of the assembled group of strips, as shown in Fig. 1, and suitable bolts 19. 1

The thin strips 12, together with edge 13 of plate 10, or in place of plate 10 a second series of like strips similarly mount-' ed and held as described, permit the convenient formation of the described die opening 14 and permit its size and shape to be conveniently and expeditiously varied, as desired, or as made necessary on account of varying kinds of work or varying conditions in the same kind of work.

The .die opening 14 in the example shown may be formed in the following manner. A pattern p (Fig. 5) of suitable material, is formed in the shape and size of the opening desired. Pattern p is then laid upon the surface 13 and thereafter the strips 12 are inserted behind bars 11 with their lower The bolts 19 and the securing bolts for bars 11 are then tightened to clamp the strips against the filler plates 16 and between the thrust plates 18. The pattern p is then withdrawn leaving an opening 14 of the desired shape and size. It is to be noted that the strips, since they are very thin, readily follow curved surfaces of the pattern and closely conform thereto, so that only slight score marks are formed on the curved portions of the strip formed by the opening 14. In practice, I have found that the strips of one thirty-second of an inch may be satisfactorily used, although strips of other thicknesses may be used as desired. The score marks formed in the curved portions ofthe formed strip may, obviously, be reduced to as small a degree as is desired by decreasing the thickness of the strips and all the strips 12 of the group need not be of uniform thickness, as shown, although the illustrated construction is preferable. For example, thick strips may be used for the flat surfaces of pattern 0 and thin strips only for the curved surfaces thereof. It is also to be noted that the size and shape of the opening i'nay be'readily varied from time to time, as desired, by simply raising or lowering one or more of the strips 12. The latter may be lowered by hammering on their upper ends and raised by driving upwardly on shoulders 20 formed by notching the strips near their upper ends. The raising and lowering of the strips for small adjustments may be accomplished in the described manner without loosening bars 11 or bolts 19. 1

The filler plates 16, are, in the illustrated embodiment, provided in upper and lower sets, as shown in Fig. 2. Considering either set, the inner end of each strip is beveled toward the rear and concaved laterally, as indicated at 21 in Fig. 4. The concavity of each strip is diiferent,'successive stripsin a rearwardly direction having a greater degree ofconcavity than preceding strips. The assembled groups of strips form therebetween a passage 22, technically known as the choke of the die head, which passage converges from the tubular member A toward outlet 14 and also changesgradually from an approximately circular cross sectional shape near member A to a flattened substantially elliptical shape adjacent the outlet 14. Other shapes of the choke passage may be made in 'a similar manner.

In each set, the plates 16 are backed up at their outer ends by pivoted thrust plates 23, which are movable inwardly by suitable bolts 24. Each plate 23 is pivoted adjacent the forward end of the die head, the upper plate 23 being connected by pivots 25 with the side plates 9 and the lower plate 23 being fulcrumed on a shoulder 25 (Fig. 2) formed on the front plate 10 near the lower end thereof. It will be readily seen that by turning bolts 24 inwardly the thrust plates may be made to simultaneously force all the plates 16 of their series inwardly.

form manner. The upper set of plates 16 may be held against inward movement by the clamping means described, and the lower set is held against inward movement by gravity action or similar clamping means. The stock forced through passage 22 tends to seat both set of plates on their members 23.

The adjustment of the choke passage is particularly important and advantageous, where the die is used in the formation of strips of rubber stock, as in tire manufacture, for example. with a constant die opening, the strip produced by being forced through the latter, may be varied in size through an appreciable range by increasing or retarding the flow of the stock to the die. The described construction permits convenient acceleration or retardation of the flow to the die opening by moving the filler plates outwardly or inwardly respectively. The adjustable choke opening is most desirable when dealing with plastic material, such as rubber stock, for example. Such material, due to its inherent plasticity and elasticity, tends to spring outwardly after leaving the confines of the die, with the result that the strip formed may be larger than the die opening. This swellage of stock necessarily .varies with the properties, particularly the elasticity, of the particular batch of material being handled,

and it has been found extremely diflicult to make each batch of rubber stock of exactly the same elasticity. The practical -difliculties arising from varying qualities of rubber stock have made it expedient to provide compensating means in the die head rather than to attempt precise uniformity of material. It will be obvious that by varying the choke passage 22 and thus varying the flow to the die opening adjustments to compennsate for the variations in the natural properties of the material being handled, may be made. The compensating adjustments may also be made byvarying the size of the die opening by the convenient means provided.

The invention has been described in a preferred embodiment for thepurposes of illustration, but the scope of the invention is more properly defined by the appended claims than by the foregoing description. l/Vhat I claim is 1. A die head, comprising, a casing pro-' vided with an inlet into which material may be forced and a die opening through which the material may emerge, a group of movable members between the inlet and die opening arranged to form a wall of a converging passage, and means to simultaneously move all said members by varying inerements increasing progressively from one end of the group to the, other.

.2. A die for forming plastic material,

It has been found that comprising, a casing formed with an inlet into which the material may be forced and a die opening through which the material may emerge in finished form, a passage formed between the inlet and' die opening having walls inclining from the former to the latter, means to vary the inclination of said walls, and means to vary the size of said opening, all constructed and arranged so that the size of the member formed by the die may be varied by the last-named means or by varying the flow to the die opening by the first-named means, or by both as desired.

3.. A die, including in combination, a front wall made up of a plurality of members mounted so that an edge of each forms an increment of a wall of the die opening and determines the shape thereof, and holding means for said members arranged to permit individual adjustment of each, whereby said members may be positioned so that the combined edges of some or all approximate curved surfaces.

4. A die, comprising, a casing, having an open end, a plurallty of thin strips stacked in face to face relation to close said open end tively small die outlet, said members being movable independently or in groups to vary the size and shape of the die outlet, and means to clamp the members to the casing.

6. A die, comprising, a casing having an inlet opening at one end and a relatively large opening at the other end, a plurality of thin strips stacked face to face across said opening, said plates being movable independently or in groups as desired to' cooperate with a fixed part of the casing to form die outlet openings of various shapes and sizes and means to clamp the plates together and to said casing.

7. A die, comprising, a casing having inlet and outlet openings, groups of movable members between said outlets, said groups cooperating with one another to form a connecting passage between said openings which converge toward the outlet opening, means to simultaneously move the members of each group by varying increments increasing progressively toward the said outlet, whereby the degree of convergence of said passage may be varied, and means to hold said members in their various positions of adjustment.

8. A die, comprising, a casing having inlet and outlet openings, a plurality of groups of members arranged within the casing to form walls of a passage which connects said openings and converges toward the outlet opening, said group comprising a plurality of plates stacked in face to face relation, a member for each group overlying the outer ends of all the plates therein and pivoted at one end near the outlet of the casing, means to move said plate on its pivot, and means to hold the plates in their adjusted positions within the casing, all constructed and arranged so that said passage may be adjusted to various degrees of convergence to vary the flow therethrough.

9. A die head, comprising, a hollow casing having an inlet at one end and a relatively large opening at the other end, a plurality of movable plates stacked face to face 'crements increasing progressively toward the inlet and means to ,clamp both groups of plates against said part.

10. A die head, comprising, a casing having a tubular inlet and a-hollow rectangular the casing, the inner ends of each group being inclined from the outlet toward the inlet, and the inner ends being laterally con- 1 caved to varying degrees so that a convergent passage gradually changing from substantially the shape of the inlet to substantially that of the outlet is provided, and

2 means to simultaneously move all the plates of each group by varying increments increasing progressively from the outlet to the inlet. o

11. A die including in combination a front wall made up of laminae, holdingmine the shape of the die opening, whereby the latter maybe changed as desired.

' GEORGE H. LEWIS. 

